Apparatus for the decantation of liquids



Aug. 5, 1969 J. DOLLFUS 3,459,368

APPARATUS FOR THE DECANTATION OF LIQUIDS Filed July 21, 1966 3 Sheets-Sheet 1 FIGJ.

INVENTOR Jacques Dollfus Aug. 5, 1969 J. DOLLFUS APPARATUS FOR THE DECANTATION OF LIQUIDS Filed July 21, 1966 3 Sheets-Sheet 2 LIGHTER LIQUID FIG. 2;

INVENTOR Jacques Dollfus BY W Aug". 5, 1969 J- DOLLFUS APPARATUS FOR THE DECANTATION OF LIQUIDS Filed July 21, 1966 3 Sheets-Sheet 3 I ll lllTL llllrllal| rlll u FI'G.3.

INVENTOR Jacques Dollfus FIG .5.

United States Patent 3,459,368 APPARATUS FGR THE DECANTATION 0F LIQUIDS Jacques Dollfus, SaintMande, France, assignor to La Societe des Ateliers Robatel et Mulatier, Lyon, Rhone,

France Filed July 21, 1966, Ser. No. 566,911 Int. Cl. 130% 15/02, 11/02 US. Cl. 233-15 6 Claims ABSTRACT OF THE DISCLOSURE Apparatus for the continuous, repeated and sequential mixing and decantation of two normally immiscible liquids of different specific gravity, comprising a tubular drum rotating rapidly about its longitudinal axis. A plurality of like, one-piece tubular sections fit within the drum in end-to-end contacting relation and rotate as a unit therewith. Each section has two integral, radially-inwardly, and circumferentially-extending flanges. The inner peripheries of the flanges extend circularly about the axis of the drum. Each pair of flanges of each section defines an annular decantation chamber between them, and each flange of one section defines with the contiguous flange of the next adjacent section, an annular mixing chamber. Lighter liquid enters a mixing chamber at a first end of the drum and is therein mixed with heavier liquid flowing from the second decantation chamber. Thereafter the mixed liquids flow together in a first direction toward the second end of the drum, through apertures in the flange, to the first decantation chamber where they are decanted centrifugally. The decanted lighter liquid then continues flow in the first direction to the second mixing chamber where it meets and is mixed with decanted heavier liquid coming from the third decantation chamber, and so on. Thus the two liquids are introduced at opposite ends of the drum, flow generally in opposite directions from chamber to chamber, and are exhausted at opposite ends.

This invention relates to a method of and an apparatus for bringing into intimate contact two liquids which are normally immiscible, in a succession of stages each consisting of mixing of the two liquids followed by separation thereof by decantation under centrifugal force. In general the two liquids traverse the apparatus in opposite directions.

The extraction of liquid from liquid finds use in an increasingly large number of industries of Which may be mentioned petroleum, chemical and nuclear; and several types of apparatuses are commonly used for this purpose. The need for low-cost extraction procedures which afford adequate time of contact or mixture between liquids has resulted in types using single or multiple columns of liquid wherein agitation of the liquids may be used to improve the intimacy and rate of mixing, and by a number of stages each consisting of mixing, followed by decanting. In general the prior art apparatuses employed depend for operation upon gravitational forces for sepa-' ration of the liquid phases which have been previously mixed. However, such devices are necessarily large and cumbersome for adequate capacity, require large amounts of space and are too expensive because of excessive cost of installation, maintenance and overhead.

The present invention avoids and overcomes the drawbacks of prior art devices by employing a series of successive stages, each consisting of the intimate mixing and agitation of two liquids, followed by their rapid separation by centrifugal force.

It is the chief purpose of the invention to provide a method of and an apparatus for the rapid, low cost, intimate mixing and subsequent decantation of two immiscible liquids, in a series of sequential steps or stages and with minimum time between stages.

A further object is to provide an apparatus which by reason of its utilization of centrifugal force, assures the processing of a high volume of liquids in a machine of moderate size and high efiiciency.

A still further object is to provide an apparatus of the kind mentioned and which is extremely versatile in the mixing and separation of various liquids and, by reason of its construction, may be built and assembled to carry out any number of stages within practicable limits.

Yet another object is to provide a cylindrical or tubular section for an apparatus of this type, and which facilitates rapid assembly and, when required, disassembly and replacement of parts; and wherein each mixing and decanting stage is effected in a single one of a plurality of sections all of which are essentially duplicates.

Another object is to provide a centrifugal type mixing and decanting apparatus which may be assembled in a number of sections by inserting into a tubular element of proper length, and in sequence, in axial alignment, an end section, a selected number of mixing-decanting sections of like construction, and a second end section, the end sections being for the introduction and extraction of the two liquids.

Other objects and advantages of the invention will become clear to those skilled in the art, after a study of the following detailed description, in connection with the accompanying drawing.

In the drawing:

FIGURE 1 is a vertical axial section through the apparatus of the invention;

FIGURE 2 is a flow diagram showing the paths of the lighter and heavier liquids through the apparatus of FIG- URE 1;

FIGURE 3 is a development of the assembled tubular sections of the apparatus of FIGURE 1, showing the various orifices in the flanges of the sections and the apertures and interconnecting conduits in the peripheral Walls of these sections;

FIGURE 4 is a detail view of one of the several identical mixing blades utilized in the apparatus; and

FIGURE 5 is a cross section in a plane identified by line 55, FIGURE 3.

Referring to FIGURE 1, a base 10 has left and right axially spaced bearing supports 11 and 12 secured thereto as by cap screws 13. The supports include rings which are counterbored to accommodate with a smooth fit, the outer races of antifriction bearings whose inner races are identified at 6 and 7, respectively.

A drum generally identified at 1, includes a tubular element 2 with a cylindrical interior wall. The element is externally thickened at its ends, as shown upon FIG- URE 1, to provide adequate area for circumferentially spaced tapped holes.

The ends of the tubular element are closed by circular end pieces or caps 3 and 4. End 3 has a central opening surrounded by an integral cylindrical outwardly-projecting collar smoothly fitting inner race 6 of one antifriction bearing. The inner face of the end has a circular shoulder 3a of a diameter for a snug fit within the contiguous end of cylinder or drum 2. A plurality of uniformly spaced cap screws 5 pass through respective holes in the end piece and are threaded into the holes in the contiguous thickened end or rim of the drum. The rim of end 3 is provided with gear teeth 17 which may, of course, be in the form of a toothed ring secured to the end in any suitable way, coaxially of the common axis of the antifriction bearings.

End 4 may be identical with end 3 except for teeth 17 of the latter, so that it need not be described in detail.

The end portions of the collars of parts 3 and 4 are externally threaded as shown. An internally threaded ring 8 engages the collar on end part 3. Likewise a ring 9 engages the collar on end part 4. Thus these two rings engage the inner races 6 and 7, respectively, and prevent end play of the drum formed by element 2 and its end closures 3 and 4. The shaft 15 of a motor 14 carries a pinion 16 in mesh with teeth 17 so that the motor when energized rotates the drum.

Base projects outwardly at each end beyond bearing supports 11 and 12. At its left end a bracket 22 is fixed to the base by a pair of cap screws 23, only one of which appears upon the figure. Likewise, at the right end a bracket 21 identical with 22 is fixed to base 10 by a pair of screws 21a. The distal end of each bracket is in the shape or a ring. The two rings are coaxial with the antifriction bearings and conjointly support a tube 19 fixed therein. As is clear from inspection of the figure, this tube passes with clearance through the central apertures in end parts 3 and 4.

A plurality of annular or cylindrical flanged sections fit snugly within the drum and are rigidly affixed thereto by keying, welding or in any other mechanically acceptable way, to rotate as a unit with the drum. In general the sections are in the exterior form of cylinders and of the same axial dimension except in the case of the two end sections. Each section is provided with a number of axially spaced internal, radially and circumferentially extending flanges. Each pair of consecutive flanges thus define an annular chamber between them.

Referring particularly to the development of FIGURE 3, the dividing planes between sections are normal to the plane of the figure and are shown in dotted lines, right to left, at 50, 51, 52, 53 and 54. The sections per se are identified generally at 55, 56, 57, 58, 59 and 60 so that in the model shown there is a total of six sections. Each section has its end surfaces in a respective one of two of the axially-spaced planes previously identified. These planes are normal to the axis of rotation of the drum, so that the end surfaces of contiguous sections make substantially liquid-tight contact. If required, sealing or gasket means may be provided between the surfaces for this purpose. All of the sections have an external diameter making a smooth fit within tubular element 2.

Right section 55 as viewed upon FIGURES l and 3 has an annular end flange 61 which is in surface contact with end piece 4 of the drum. The circular opening defined by this flange has a diameter a little greater than the internal diameter of the sleeve integral with end 4. Section 55 also has an annular flange 62 spaced axially from flange 60 to define therewith an annular channel for one of the two liquids to be treated, in this case, the heavier liquid.

The next section 56 has two integral axially-spaced flanges 63 and 64, FIGURES 1 and 3. The annular channel defined by and between flanges 62 and 63 is for the collection and egress of the lighter liquid, while the channel defined by and between flanges 63 and 64 is for decantation of the two intermingled liquids.

As will become clear from the fOllOwing description, the sections 56, 57, 58 and 59 may be identical except for their rotational positions in the assembly and the radial distances from the central axes thereof, of the egress holes in their flanges. Hence, referring in particular to the development of FIGURE 3, it is suflicient to identify flanges 65, 66 of section 57, flanges 67, 68 of section 58, and flanges 69, 70 of section 59.

Left end section 60 is of special construction and includes two flanges 71, 72, and end flange 73. Referring to FIGURE 1, there is an integral frusto-conical partition 74 between and interconnecting flanges 71 and 72, for the purpose of directing the entering lighter liquid to the first mixing chamber at the left, and for directing the decanted heavier liquid into its egress channel. For convenience and simplicity of description the several channels thus formed are identified by numerals 30, 31, 32,

4 etc., through 41, FIGURE 3. End flange 73 has a central opening of the same diameter as the corresponding one in flange 61 at the right end of the apparatus.

Referring to FIGURE 3, channels 32, 34, 36 and 38 are for decanting, and channels 33, 35, 37 and 39 are for mixing, and have a smaller axial dimension than the decanting chambers.

Fixed central tube 19 has been previously described. This tube mounts a plurality, four in the apparatus shown, of mixer disks or blades identified upon FIGURE 1 at 42, 43, 44 and 45. One of these, 45, is shown in detail upon FIGURE 4. Each blade is fixed with the tube and is positioned axially thereof and centrally within a respective one of the mixing channels 33, 35, 37 and 39. The blades may be unitized with spacer sleeves such as 46 which fit on and about the tube. Since the planes of separation between sections 55, 56 etc., are located within a respective one of the mixing chambers, assembly is facilitated by first sliding on an end spacer sleeve 46, securing it to tube 19 as by set screws, not shown, adding a mixer blade and fixing it to the sleeve, then adding a chamber or channel section such as 59, adding the next sleeve and so on until the assemblage is completed and the other end sleeve 46 is emplaced.

By the construction just described, as the drum and its channel sections are rotated rapidly with respect to fixed mixer blades 42, 43, 44 and 45, the two liquids in the several mixing channels are broken up and intimately intermingled. From FIGURE 4 it is noted that the periphery of each blade such as 45, is provided with notches 47 for increasing the agitation of the two liquids.

Means extending in and along tube 19 are provided to respectively feed and extract lighter liquid to and from the apparatus and to feed and extract heavier liquid.

A first tube 24 extends from a source of lighter liquid under pressure, not shown, from right to left. At its distal end this tube is connected with a 90 fitting 25. The fitting carries a nozzle 26 which extends radially through an aperture in the wall of the tube and terminates within the radially inward channel defined by partition 74 between fianges 71, 72. Thus lighter liquid is fed under pressure into this channel, at a controlled rate.

Another feed tube 27 extends in and along tube 19, from a source of heavier liquid under pressure, not shown, and has a 90 fitting or elbow 28 fixed to its end within the tube. This elbow mounts a nozzle 29 which extends through an aperture in the wall of tube 19 and terminates within channel 30 so that heavier liquid may be fed into this channel at a controlled rate and at the end opposite to that to which lighter liquid is conducted. As shown, both feed nozzles 26 and 29 are directed downwardly from tube 19.

After passing through the several channels in succession, lighter liquid is withdrawn through a pipe 75 ex tending in and along tube 19, FIGURE 1. The end of this pipe within the tube carries a 90 fitting 76 to which is fixed a pipe section 77 extending through an aperture in the wall of the tube and protruding into channel 31. The distal end of this pipe section is curved or bent or turned so that its opening faces in the direction away from the direction of rotation of the drum. As shown, this section is directed generally upwardly. As the end thereof is radially outwardly of the cylindrical surface of the liquid, created by centrifugal force of the rotating drum, a component force acts to impel liquid into pipe section 77 and along pipe 75. This force may, of course, be augmented by a source of reduced pressure to increase and/ or to control the rate of flow of lighter liquid passing from the apparatus.

Likewise a pipe 78 for exhausting heavier liquid extends in and along tube 19 and has a 90 fitting 79 fixed to its distal end. A pipe section 80 communicates with the fitting and extends radially upwardly through an aperture in the tube, to terminate within end channel 41. As in the case of pipe 77, the end of pipe section 80 is directed at an angle opposite to the direction of rotation of the drum, so that a component force due to momentum of the rotating liquid acts or assists to impel liquid into and along pipe 78 for collection exteriorly of the apparatus. The angle at which the distal ends of pipe sections 77 and 80 are directed, may be between and 30 with respect to the tangent to the annular surface of the liquid at that point. An angle of about is preferable, as shown for pipe 77 in dotted lines, FIGURE 5. Heavier liquid thus enters through pipe 27 and is exhausted through pipe 78, while lighter liquid enters through pipe 24 and is exhausted through pipe 75.

A series of orifices in the flanges, and longitudinally extending channels or conduits formed in the peripheral surfaces of the sections, guide and direct the two liquids from chamber to chamber in proper sequence. Confining attention to the heavier liquid entering chamber 30, and referring to FIGURE 3 in particular, there are shown three orifices 81 in the periphery or outer wall of chamber '30. These orifices as shown, are preferably uniformly circumferentially spaced and each is in communication with a respective one of three longitudinally extending conduits 82 formed in the outer surface of the sections 55 and 56. These conduits extend to and terminate in an equal number of orifices 83 through the peripheral wall of chamber 33. Heavier liquid entering chamber 30 may thus flow to mixing chamber 33 where it is mixed with lighter liquid also flowing into the chamber, as subse' quently described.

Flange 64 forming one wall of chamber 33 has three apertures 84 therethrough. From FIGURE 1 it is seen that these apertures are spaced radially inwardly from the peripheral wall of section 56 a distance such as will permit the intermingled lighter and heavier liquids to flow from chamber 33 to the right, into decantation chamber 32. Only two of these apertures 84 appear upon FIGURE 3 because the development does not extend through the full 360 of the sections. It will be understood that the third aperture is in flange 64 below the lowermost conduit 82, as viewed upon FIGURE 3.

In chamber 32 the two liquids are separated by centrifugal force of the rotating drum and the heavier liquid leaves by one of theree uniformly spaced orifices 85 in the peripheral wall of the chamber 32. Only two of these orifices appear upon FIGURE 3. Each orifice communicates with a respective conduit 86 leading to and in com munication with a respective orifice 87 in the peripheral wall of mixing chamber 35.

In chamber 35 the heavier liquid is again broken up and intermingled with lighter liquid coming from the left. The intermingled liquids then pass together to the right through any one of three orifices 88 in flange 66, and enter decantation chamber 34.

After decantation in chamber 34 the heavier liquid exits by way of any one of three orifices 89 in the peripheral wall of this chamber and, passing through conduits 90, enters mixing chamber 37 through orifices 91. The liquids, intermingled in chamber 37 with the aid of blade 44, pass together through apertures 92 in flange 68, to the right and into chamber 36 where decantation again takes place. From this chamber the decanted heavier liquid enters orifices 93, passes leftwardly through conduits 94 and enters mixing chamber 39 through orifices 95. An other mixing of the liquids occurs in chamber 39 and the two return through apertures 96 in flange 70 to chamber 38 where a final decantation takes place and the heavier liquid passes into orifices 97 in the peripheral wall of this chamber and flows through conduits 98 to end cham ber 41 where it is collected to intake pipe 80 and,conducted through pipe 78 to storage externally of the apparatus.

It should be noted at this point that whereas FIGURE 1 shows apertures and orifices such as 81, 85, 84, 83, etc., in a common axial and radial plane, this is for con* venience and ease of understanding of the paths of the two liquids; and that FIGURE 3 shows the actual preferred circumferential spacing and offset between the several apertures and orifices. This spacing is not haphazard but, to the contrary, enables all sections 56 through 59 to be cast in the same mold and assembled with the apertures in one flange properly offset from those in the contiguous flange of the next adjacent section.

Thus the heavier liquid in each stage passes radially outwardly of the decantation chamber, to the corresponding mixing chamber, reverses its flow with the lighter liquid, passes through apertures in the flange between these two chambers, is decanted, and again fiows leftwardly to the next mixing chamber. While the flow of heavier liquid is from right to left as viewed upon FIGURES 1, 2 and 3, it will be understood that the flow may be from left to right.

The lighter liquid has a more direct passage through the apparatus. Entering from nozzle 26, FIGURE 1, into chamber 40, the lighter liquid first traverses apertures 10 0 in flange 71, into mixing chamber 39 where it is rapidly broken up into globules of microscopic size by blade 45 in this chamber, and immediately intermingled with heavier liquid coming through orifices 95.

The mixed liquids then pass together through apertures 96, into decantation chamber 38 where the two are separated by centrifugal force as the heavier liquid is urged outwardly toward the peripheral wall of the chamber and thus forces the lighter liquid inwardly into a radiallyinward, ring-like body from which it passes through orifices 101 in flange 69 to mixing chamber 37. From FIG- URE 1 it is noted that the orifices 101 through which the lighter liquid passes, are radially inwardly with respect to orifices such as 96, through which the mixed liquids pass. These orifices 101 are generally located at a radial position at the inner free surface of the decanted lighter liquid. This radial position will, of course, be determined by the normal capacity or rate of flow for which the particular apparatus is constructed, and is a matter of computation. On the other hand, the apertures such as 96 through which the mixed liquids fiow are positioned radially outwardly of the corresponding apertures 101, 102, etc., in the flanges forming the side walls of the mixing and decantation chambers.

Since the flow of mixed liquids through apertures 92 in flange 68, between chambers 37, 36, through apertures 88 in flange 66, between chambers 35, 34, and through apertures 84 in flange 64 between chambers 33 and 32, has been previously described, it is deemed sufficient merely to identify the apertures through which the decanted lighter liquid flows, namely, orifices 102 in flange 67, 103 in flange 65, and 104 in flange 63. Although not especially critical, the positions of the several orifices in the flanges, and conduits in the peripheral walls of the tubular sections such as 56, 57, etc., is preferably as depicted upon the development of FIGURE 3. Thus, for example, each set of conduits such as 82, and 98 will lie in a common radial plane through the axis of rotation of the drum; conduits 86 and 94 will be in another common radial plane, each set of orifices 84, 88, 92 and 96 in a third radial plane, and so on. While on FIG- URE 3 only two orifices 96 in flange 70, 92 in flange 68, 88 in flange 66, and 84 in flange 64, are shown, it will be understood that this is because the figure does not show a full 360 development, and that actually there are three each of these, equiangularly spaced as in the case, for example, of apertures 103 in flange 65.

Merely as one example of an operative apparatus, drum 1 has an external diameter of 450 mm., with four stages of mixing and decantation each. The capacity of each mixing chamber is about 0.5 liter and of each decantation chamber, about 2 liters. The drum may be rotated at about 2,900 r.p.m. and for the liquids subsequently identified, processes about 500 liters of liquids per hour. The rate of flow is adjusted so that any given small mass of liquid traverses the apparatus in about 36 seconds. The foregoing relates to two liquids such as a heavy liquid uranyl nitrate having a density at 20 C. of about 1.209, free acidity about 2.46 and containing about 39.35 grams per liter of uranium. The lighter liquid of tributyl phosphate has a density of about 0.833 in a 30% solution of TBP in dodecane. When equilibrium of operation has been established, about 97% of the uranium of the initial aqueous phase, is recovered in the organic phase.

The operation will be clear from the preceding description. The heavier liquid is continuously introduced into chamber 30 and flows right to left through four stages of mixing and decantation each, and is withdrawn from chamber 41. The lighter liquid is continuously introduced into chamber 40, flows left to right through the same four stages, and is withdrawn from chamber 31.

FIGURE 2 shows schematically the directions of flow. In this figure the flow of heavier liquid is indicated in dotted lines and that of the lighter liquid in solid lines. The two rates of flow may be controlled so that stoichiometric amounts of the active ingredients are present in each mixing chamber at all times. It is also contemplated that, if desired, or found necessary, metering means may be provided in each of the several conduits such as 82, 86, 90, 94 and 98. For example, such means may take the form of simple threaded elements passing radially through the wall of tubular element 2 and having ends protruding into each respective conduit so that the eflective size of the conduits may be altered by adjustment of corresponding ones of the threaded elements inwardly or outwardly, as desired.

While I have shown the apparatus in specific form, it will be understood that this is by way of example only and that numerous changes in shape, form, construction, arrangement and number of stages, and rearrangement of conduits, apertures and orifices, will become clear to those skilled in the art, after a study of the foregoing description. Hence the disclosure should be taken in an illustrative rather than a limiting sense; and all modifications within the scope of the subjoined claims are reserved.

Having fully disclosed the invention, what I claim and desire to secure by US Letters Patent is:

1. Apparatus for sequentially mixing and decanting first and second normally immiscible liquids of different specific gravity, comprising, a cylindrical tubular element having a central longitudinal axis, first and second end caps secured to and closing the respective ends of said element, a plurality of one-piece, discrete, cylindrical tubular main sections each having an essentially smooth exterior surface fitting within and secured to said element, in end-to-end contact extending along and coaxially about said axis, each said section including first and second axially-spaced flanges integral therewith and extending radially inwardly toward, and circumferentially about said axis, the flanges of each said section defining between them a respective one of a plurality of annular decantation chambers, each said flange in conjunction with the contiguous flange of the next adjacent section, defining a respective one of a plurality of annular mixing chambers, first passageway means comprising first apertures in each alternate one of said flanges, second passageway means comprising second apertures in each remaining one of said flanges, third passageway means comprising longitudinally-extending conduits formed in the outer peripheral wall of each said section, each said conduit having one end in communication with an orifice in and through the peripheral wall of a decantation chamber, and its other end in communication with an orifice in and through the peripheral wall of a mixing chamber.

2. The appaartus of claim 1, and first and second cylindrical end sections fitting within said element and each in end-to-end contact with a respective terminal one of said main sections, each said end section including integral first and second axially-spaced, radially inwardly and circumferentially extending flanges, the flanges of said first end section defining between them an annular chamber for the introduction of a first liquid, the flanges of said second end section defining between them an annular chamber for the introduction of a second liquid.

3. The apparatus of claim 2 the inward flange of at least one said end section defining with the contiguous flange of the next adjacent main section, an annular chamber for the exhaustion of one of the decanted liquids.

4. The apparatus of claim 3, all said flanges having open centers coaxial about said axis, a fixed tube passing along and coaxially of said axis, through said open centers, and a plurality of generally circular mixing blades each mounted on said tube and disposed, each in a respective one of said mixing chambers.

5. The apparatus of claim 1, all said main sections being essentially duplicates, the dividing planes between sections passing through each mixing chamber between and spaced from the flanges thereof, normal to said axis.

6. The apparatus of claim 5, said conduit in each said main section being uniformly spaced in and about the peripheral wall thereof, each of said first and second apertures being in a radial plane through said axis, between a circumferentially consecutive pair of said conduits, said first and second apertures lying on and being uniformly spaced along the circumference of respective first and second circles each centered on and spaced along said axis, said first circles having equal radii, greater than the equal radii of said second circles.

HENRY T. KLINKSIEK, Primary Examiner US. Cl. X.R. 23318 

